Furnace



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FURNACE. APPLICATION FILED NOV. 20, I915: RENEWED MAY 8,1919. I 1,324,883. Patented Dec. 16,1919.

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FURNACE.

APPLICATION FILED NOV. 20, 1915. RENEWED MAY 11,1919.

1 324,883. I Patented Dec. 16, 1919.

3 SHEETS-SHEET 2.

W M. DUNCAN.

FURNACE.

APPLICATION FILED NOV. 20, I915. RENEWED M AY 3,19l9.

Patented Dec. 16, 1919.

3 SHEETS-SHEET 3- UNITED STAT PATENT WILLIAM M. DUNCAN, 0F ALTON, ILLINOIS.

FURNACE.

Specification of Letters Eatent.

Application filed November 20, 1915, Serial No. 62,507. Renewed May 8,1919. Serial No. 295,699.

To all whom it may concern: I

.Be it known that 1, WILLIAM M. DUNCAN, a citizen of the United States of America, residing at Alton, in the county of Madison, State of Illinois, have invented certain new and useful Improvements in Furnaces, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention relates to improvements in furnaces, one, of the objects being to produce an efficient draft appliance for controlling the flow of air toor from an endless chain grate. lVith this object inview, the preferred form of the invention comprises rows of draft boxes arranged longitudinally of the chain grate, endless chains traveling between said draft boxes, and fuel supporting members secured to said endless chains and extending over the draft boxes. The draft boxes are preferably closed at their ends and open at the top so that the air will escape through the chain passageways.

Another object is to provide an efficient means for regulating the draft at different portions of the fuel bed.

A further object is to produce a simple means for cleaning the draft boxes.

With the foregoing and other objects in view the invention comprises the novel construction, combination and arrangement of parts hereinafter more specifically described and illustrated in the accompanying drawings wherein is shown the preferred embodiment of the invention; however, it is to be understood that the invention comprehends changes. variations and modifications which come within the scope of the claims hereunto appended.

Figure I is a longitudinal section of a furnace embodying the features of my invention. I I

Fig. II is atop or plan view illustrating the endless fuel carriers and the draft boxes associated therewith, some of the fuel carrlers being omitted.

Fig. III is an enlarged vertical section taken approximately on line IIIIII, F 1g. I.

Fig. IV is an enlarged detail view showmg a portion of the means for opening and closing the clean-out openin s through which ash, and the like, may be forced in response to the air pressure in the draft boxes.

Fig. V is a section taken approximately on the line VV, Fig. IV.

1 designates the side walls of a furnace, and 2 designates tracks located between said side walls. Side frames 3 and 4 are provided with wheels which rest upon the tracks 2. A power shaft 5, mounted in the side frames at the front of the grate, is provided With a series of sprocket wheels 6 which lie between the side frames 3 and 4. An idle shaft 7 at the rear of the grate is provided with idle wheels 8. The wheels 6 and 8 constitute supporting elements for a series of endless traveling fuel carriers, and each of these fuel carriers comprlses an endless sprocket chain 9 fitted to one of the sprocket wheels 6 at the front of the grate and also fitted to an idle wheel 8 at the rear of the grate. Each fuel supporting member is a rectangular plate 10 having perforations for the admission of air to the fuel and provided with legs12, the ends of said legs being secured to a pair of pivot pins forming part of the endless chain structure.

To prevent undueleakage of air and fuel, each longitudinal row of fuel carriers laps the next adjacent row or rows(see Fig. III). The fuel carriers 10 at the sides of the grate structure lap and rest upon the side frames 3 and 4 as shown in Fig. III, and two margins of the other fuel carriers 10 lap the side margins of two other fuel carriers. In other words, all of the fuel carriers 10 excepting those at the sides of the grate, are provided with extensions 10 and 10 which lap each other, as shown in Fig. III, the fuel carriers at the sides of the grate being provided with similar extensions which lap one of the intermediate rows of fuel carriers. The fuel Patented Dec. 16, 1919. i

supporting members of each row also lap each other, as shown in Fig. I. By lapping the rows of fuel carriers, and also lapping the fuel carriers of each row, I prevent leakage of fuel, ash and air at all points around the four margins of each fuel carrier. It may be noted that the lapped edges of the fuel carriers of each row separate from the adjacent fuel carriers of the same row in passing around the supporting wheels at the ends of the grate, but the fuel carriers of one row does not separate from the adjacent fuel carriers of the adjacent row or rows in passing around 'said wheels.

13 designates the usual coal hopper at the front of the grate, said hopper being open at the bottom to permit the coal to pass onto the grate in a manner well understood in this art.

Each fuel supporting member tilts in passing around an idle wheel 8 at the rear of the grate, and the ash is discharged into an opening 14 as indicated by arrows in Fig. I. It is important that the ash be discharged at a predetermined point, and to insure the discharge of all, or almost all, of the ash into the opening 1 1, I arrange a series of arcuate deflectors 15 at the rear of the grate, as shown in Figs. I and II. The legs 12 of the fuel supporting members 10 lie between arcuate deflectors 15, and the latter serves as guides for the fuel supporting members. These deflectors 15 deflect the ash rcarwardly, from the discharging fuel supporting members, to points beyond the preceding fuel supporting members, so that the ash will not be discharged onto the last mentioned members.

I will now describe means for controlling the admission of air to different parts of the fuel bed. Manifolds 17, 18 and 19, arranged transversely of the grate structure, are secured at their ends to the side frames3 and 4. Air conducting pipes 20, passing through the furnace wall 1, are fitted to the manifolds and provided with valves 21 for regulating the flow of air through said manifolds. Each valve 21 is capable of controlling the draft in only one of the manifolds, and these valves may be adjusted independently of each other. The air conducting pipes 20. leading to the different manifolds, are merely forced into the manifolds and they may be withdrawn through the furnace wall 1 to permit the removal of the entire grate structure from the furnace.

The draft boxes for conducting air from the manifolds to the fuel bed, are arranged longitudinally of the grate, and each manifold is in communication witha series of the draft boxes. The manifold 17, near the front of the grate, communicates with draft boxes 23 and 23', the boxes 23' being located at the sides of the grate, and the draft boxes 23 being located between said draft boxes 23'. These draft boxes are seated eas es passageways 25 for conducting'air to the draft boxes 23 (see Fig. III). Each of the draft boxes 23 and 23 is closed at its front end by a wall 26, and closed at its rear end by a wall 27, said front and rear walls being connected by a bottom wall 28 and side walls 29. From the foregoing, it will be understood that each of the draft boxes 2323' is closed at its sides and ends, and open at the top to permit the air under pressure to circulate through the perforations in the fuel supporting members 10. Chain passageways 30 are formed between the draft boxes to receive the endless sprocket chains 9. These chain passageways are necessarily open at their ends, but since they are not in communication with the draft boxes, the air cannot escape by passing out through the open ends of the chain passageways. Thatis to say,the chain passageways anddraft boxes are so formed that the chains may travel continuously between the draft boxes, and the air passing into the draft boxes cannot escape intothe chain passageways.

Intermediate draft boxes '31 and 31, similar to the draft boxes 23 and 23, are provided with end walls 32 and bottom and side 'walls connecting said end walls. All of these intermediate draft boxes 31 and 31 are in communication with the manifold 18, and they are separated from each other to permit the sprocket chains to pass between them. Rear draft boxes 33 and 33' are provided with end walls 34 connected by side and bottom walls, said rear draft boxes 3333 being in communication with the manifold 19.

The front, intermediate and rear draft boxes are connected together to form several longitudinal rows of draft boxes, but the draft boxes 2323, near the front of the grate, are not in communication with the intermediate or rear draft boxes; and the intermediate draft boxes 3131 are not in communication with any of the other draft boxes.

The air passing through the manifold 17 is forced through the fuel supporting mem bers at points immediately above said draft boxes 23-'23. The air forced through the manifold 18, passes from the top of the intermediate draft boxes 31 at points between their end walls 32; and the air forced through the manifold 19 passes upwardly from the rear draft boxes 3333 at points between their end walls 34. It will be ob- .servedthat the draft boxes are arranged to form three draft zones,one near the front of the grate, one at the middle portion of the grate, and one at the rear. The draft in an one of these zones maybe regulated by a justing one ofthe valves 21, and the draft masses in any one zone may be varied without changing the draft in any other zone.

The c ain passageways formed between the draft boxes, are open at the top to receive the legs 12 which extend downwardly from the" fuel supporting members 10. These fuel supporting members restupon the upper edges of the draft boxes, and they extend over said draft boxes as shown most clearly in Fig. III, said members 10' being lapped at points midway between the side walls of the draft boxes.

' bers 10. Guide members 41, extendln for.-

wardly from the front ends of draft oxes 23, are adapted to guide the fuel supporting members as they pass onto the draft boxes. v Discharge openings 41 are formed in the oottoin of each draft box, said discharge openings being normally closed by doors or closures 42. The closures 42 in each row of draft boxes are secured together by a- .con- .necting bar 43, so that all of said closures may be operated at the same time. The means for operating the closures comprises a rock shaft 44 havmg a seriesjof bifurcated arms 45 which lie immediatel below the closures 43' near the front 0 the grate. Each of the last mentioned closures has a depending lug 46 (Fig. I) which is loosely secured to the upper end of one of the arms 45. The means for actuating the rock shaft 44 comprises an arm 47 securedlto one end of said rock'shaft, and an operating rod. 48 connected to said arm. When the grate is in service, ash, fine particles of fuel, and

the like, will drop through the perforations in the fuel supporting members and fall supporting members and discharged therei from at points near the sprocket wheels 6.

I claim 1. In a furnace,draft boxes arranged to form air passageways, chain passageways being formed between said air passageways, and traveling fuel carriers including chains in said chain passageways and fuel supporting members carried by said chains, said fuel supporting members being extended over said air passageways.

2. In a furnace, draft boxes arranged to form air passageways, chain passageways being formed between said air passageways, and traveling fuel carriers including chains in said chain passageways and'fuel supporting members carried by said chains, said .fuel supporting members being extended over said air passageways, the chain passageways being open at both ends-to permit the chains to travel therethrough and the air passageways being closed at their ends and open at the top to permit the flow of air through said fuel supporting members.

3'. In a' furnace, rows of draft boxes, traveling fuel carriers arranged partly between and partly above said draft boxes, the fuel supporting elements being located above the draft boxes. and the latter being open at the top to permit the flow of air to said fuel supporting elements, and means for conducting air to said rows of draft boxes.

4. In a furnace, rows of draft boxes, eac of said rows being arranged longitudinally of the furnace, fuel supporting members immediately above said draft boxes, means for conducting air to said draftboxes, and

traveling chalns located between the draft boxes and secured to said'fuel supporting members.

5. In a furnace,-draft boxes arranged to I form air passageways, and endless fuel carriers including fuel supporting plates adapted to travel over said draft boxes, each of said fuel supporting plates having an extension adapted to travel between said draft boxes, and endless chains secured to said extensions and arranged to travel between said draft boxes.

WILLIAM M. DUNCAN. 

